<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圆球游戏</title>
    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
    <style>
        body {
            margin: 0;
            padding: 0;
        }

        .container {
            margin: 0;
            padding: 0;
            position: absolute;
            width: 440px;
            height: 440px;
            background-color: blanchedalmond;
            display: inline;
        }

        .ball {
            position: absolute;
            width: 60px;
            height: 60px;
            left: 100px;
            top: 100px;
            background-color: red;
            border-radius: 30px;
            z-index: 100
        }
    </style>
</head>

<body>
    <div id="Application">
        <!-- 外层的div为游戏面板，小球需要在此容器中移动 -->
        <div class="container" @mousemove.stop="move">
            <!-- 此div元素表示小球 -->
            <div class="ball" :style="{left: offsetX+'px', top:offsetY+'px'}">
            </div>
        </div>
    </div>
    <script>
        const App = {
            data() {
                return {
                    offsetX: 0,
                    offsetY: 0
                }
            },
            methods: {
                move(event) {
                    /*
                    clientX  鼠标位置相对当前body容器可视区域的横坐标
                    pageX  鼠标位置相对整个页面的横坐标
                    screenX   鼠标位置相对设备屏幕的横坐标
                    offsetX 鼠标位置相对父容器的横坐标
                    x   与screenX意义一样
                    */

                    // 检查右侧不能超出边界
                    if (event.clientX + 30 > 440) {
                        this.offsetX = 440 - 60

                        // 检查左侧不能超出边界
                    } else if (event.clientX - 30 < 0) {
                        this.offsetX = 0
                    } else {
                        this.offsetX = event.clientX - 30
                    }

                    // 检查下侧不能超出边界
                    if (event.clientY + 30 > 440) {
                        this.offsetY = 440 - 60

                        // 检查上侧不能超出边界
                    } else if (event.clientY - 30 < 0) {
                        this.offsetY = 0
                    } else {
                        this.offsetY = event.clientY - 30
                    }
                }
            }
        }
        Vue.createApp(App).mount("#Application") 
    </script>
</body>

</html>